Interchangeably structured electrical cartridge with cross-biased latch mechanism for the releasably tethered cap of the same

ABSTRACT

The cartridge is interchangeably structured to accommodate various servomechanisms for the switch unit or other operating unit therein, as well as to accommodate various electrical arrangements for the pushbutton cap which is slidably guided in the open end of the cartridge to operate the servomechanism. The cap is releasably latched to each servomechanism by a crossbiased latch mechanism which prevents the cap from being shocked out of the cartridge, but which can nevertheless be overridden by a finger pull on the cap when it is desired to remove the cap from the cartridge. When so removed, the cap is tethered to the cartridge, although the tether is releasable from the cap, and vice versa, should this become necessary or desirable.

United States Patent 1191 Fuller INTERCHANGEABLY STRUCTURED ELECTRICALCARTRIDGE WITH CROSS-BIASED LATCH MECHANISM FOR THE RELEASABLY TETHEREDCAP OF THE SAME [75] Inventor: Maurice D. Fuller, Mercer Island,

Wash.

[73] Assignee: Korry Manufacturing Company, Seattle, Wash.

[22] Filed: June 26, 1972 [21] Appl. No.: 266,305

[52] U.S. c1 200 3211, 74/527 [51] Int. Cl. H0lh 3/20, H0lh 9/20 [58]Field of Search..... 74/527; 250/169 R, 169 PB, 250/167 A [56]References Cited UNITED STATES PATENTS I 2,958,838 11/1960 Puerner338/215 X 3,252,721 5/1966 Weasler 74/527 UX 3,604,878 9/1971 Amis et al200/169 PB X 1451 July 16, 1974 3,696,222 10/1972 Langan et al. 200/169PB X Primary ExaminerRobert K. Schaefer Assistant ExaminerWilliam J.Smith Attorney, Agent, or FirmChristensen, OConnor,

Garrison & Havelka [57] ABSTRACT The cartridge is interchangeablystructured to accommodate various servomechanisms for the switch unit orother operating unit therein, as well as to accommodate variouselectricalarrangements for the push- -button cap which is slidablyguided in the open end of the cartridge to operate the servomechanism.The cap is releasably latched to each servomechanism by a cross-biasedlatch mechanism which prevents the cap from being shocked out of thecartridge, but which can nevertheless be overridden by a finger pull onthe cap when it is desired to remove the cap from the cartridge. When soremoved, the cap is tethered to the cartridge, although the tether isreleasable from the cap, and vice versa, should this become necessary ordesirable.

34 Claims, 11 Drawing Figures PATENTEDJUL x e 1914 mums INTERCHANGEABLYSTRUCTURED ELECTRICAL CARTRIDGE WITH CROSS-BIASED LATCH MECHANISM FORTHE RELEASABLY TETHERED CAP OF THE SAME FIELD OF THE INVENTIONBACKGROUND OF THE INVENTION INCLUDING CERTAIN OBJECTS THEREOF Assembliesof this nature are widely used in the electrical industry, particularlyin electrical cartridges which are mounted on a panel, either asindividual units, or collectively as a keyboard of the same. Eachcartridge is equipped with a cap which is slidably guided in the openend thereof to serve as the pushbutton actuator for a servomechanismwhich is mounted in the cartridge in advance of an operating unit, suchas a switch unit, which is actuated thereby. The cap is usuallyilluminated to reveal intelligence thereon which is indicative of thenature or condition of the operating unit, and is preferably removablefrom the cartridge so that the illuminating lamps therein can bereplaced when necessary. It is desirable, however, that the cap not betotally detachable from the cartridge, but instead be tethered to thesame, so as to assure that it is not separated and lost when it isremoved for the relamping operation. It is also desirable that the capbe securely latched to the servomechanism, when it is returned to thecartridge, so that forces acting on the cartridge during normal use andabuse of the same, such as shock forces, will not dislodge the cap andprevent it from being always readily available for the servofunction.

One object of the present invention, therefore, is to provide amechanism whereby the cap can be releasably latched to the cartridge,when it is inserted therein, and the cartridge can be expected towithstand shock forces of limited duration and extent without the capbecoming dislodged therefrom, yet the latch mechanism can be overriddenby a finger pull on the cap when it is necessary or desirable to removeit from the cartridge. Another object is to provide a latch mechanism ofthis nature whereby the cap can be latched to the servomechanism in thecartridge, and can become a part thereof for purposes of actuating theoperating unit in the cartridge. A further object is to provide a latchmechanism of this nature which is adapted to function with any one ofseveral servomechanisms, which may provide among them, for example, amomentary action effect, an alternate action effect, a latch and unlatcheffect with respect to other cartridges in a keyboard of the same, orsome other similar special effect which is suited to the operation ofthe unit inboard of the cartridge. A still further object is to providea mounting base for the servomechanism whereby it can be readilyinterchanged with another such mechanism,

notwithstanding that the same cap is retained and operably latched tothe servomechanism as described. Still another object is to provide anintermediate actuator within the servomechanism, which is operable toactuate the operating unit while providing a degree ofovertravel for theservomechanism otherwise. An additional object is to provide anelectrical contact assembly, and a mounting technique for the same,whereby various electrical arrangements can be achieved in thecartridge, for purposes of illuminating thecap in such a way as toreveal different intelligence, or different combinations of intelligenceon the cap. Still another object is to provide a mechanism whereby thecap is tethered to the cartridge, in the removed position thereof, yetcan be released from the tether by a few simple steps that are readilyexecuted with ones hands. Still further objects will become apparentfrom the description of the invention which follows hereafter.

SUMMARY OF THE INVENTION These objects and advantages are realized by areleasable latch mechanism of my'invention which is adapted to cooperatewith a relatively reciprocable member, and comprises means defining astop about the path of reciprocation of the-member, and a latch elementwhich is reciprocable in parallel with the member, independentlythereof, and yieldably biased in a direction lengthwise of the path ofreciprocation of the member, into engagement with the stop, as well asyieldably biased in a direction transverse of the path, to assumea'position thereon. The mechanism also comprises detent means which areoperable to interengage the latch element and the member, when themember is reciprocated against the bias on the element in the directiontransverse of the path; as well as latch release means whichare operableto disengage the latch element and the member, when the member isreciprocated against the bias on the latch element in the directionlengthwise of the path.

Preferably, the latch element has a flexible portion thereof which iscantilevered into the path of the member, from a point outside thereof,and which is deflectable by the member, relatively out of the path, whenthe member is reciprocated in the direction of the bias on the element,lengthwise of the path; but which relaxes into engagement with themember, to reciprocate in conjunction therewith, when the member isreciprocated in the direction opposed tothe bias on the element,lengthwise of the path. The latch release meaans is operable in turn,however, to redeflect the portion of the element, relatively out of thepath, after the element has undergone a period of lost motion, in thedirection opposed to the bias thereon, lengthwise of the path.

For example, the member may be elongated in the directions ofreciprocation, and the flexible portion of the element may take the formof a leaf spring which is cantilevered from a carrier element that iscoaxially disposed with the member, about the path of reciprocationthereof, and slidably engageable by the member in the course ofreciprocation thereof. The detent means may take the form of a recess inthe member, into which the spring relaxes from they deflected conditionthereof; and the latch release means may take the form of a bearingsurface which is inclined to the path of reciprocation of the member,and slidably engageable with the spring, to deflect the springrelatively out of period of lost motion, in the direction opposed to thea bias thereon, lengthwise of the path.

In the presently preferred embodiments of the invention, the membertelescopically engages in a socket which has an annular shouldertherein, about the path of the member, and pairs of oppositely disposedramps therein, which are interposed between the shoulder and the mouthof the socket, on opposite sides of the path,

and inclined toward the opening within the shoulder.

The carrier element takes the form of a ring which is disposed in thesocket, coaxially with the path of the member, and has a pair ofcodirected leaf springs on diametrically opposite sides thereof, whichtogether with the ring form a U-shaped spring clip within which themember is slidably engageable in the course of recipr'ocation thereof.The member has a flange thereon, and the tips of the leaves of the clipengage in a circumferential groove in the member, when the flangeengages a stop adjacent the mouth of the socket. The leaves have flangesthereon, however, which slidably engage on the ramps, so as to deflectthe leaves from one another, when the clip is reciprocated against thebias of a coiled spring which is interposed in the socket,

between the ring and a second annular shoulder therein, that is disposedadjacent the mouth of the socket and opposed in orientation to the firstmentioned shoulder.

Where the latch mechanism is used in latching a cap to an open-endedcartridge of the type mentioned earlier, the latch element, the stop,and the latch release means are normally incorporated into the cap,whereas the detent means is embodied on a member in the cartridge. Themember may take the form of a shaft which is incorporated in aservomechanism for an operating unit which is mounted in the cartridge.Moreover, the shaft may be reciprocable and may have a flange thereon,so that the operating unit can be actuated by unidirectional forcesapplied to the flange, in the direction of reciprocation of the shaft,relatively inward of the cartridge.

Furthermore, the cartridge may be one of a keyboard of the same, and thekeyboard may have a mechanism incorporated therein whereby the forceapplied to the flange on the shaft of one cartridge, operates to latchthe respective servomechanism in the operating position thereof, whilesimultaneously releasing the servomechanism of another cartridge, fromthe operating position thereof. Also, in this same connection the shaftin each cartridge may be telescopically engaged with the respectiveservomechanism therein, and may be yieldably biased in the direction ofreciprocation, relatively outward of the cartridge, so that the cap isreturned to the normal position thereof, each time a force is applied toths same. in fact, the bias may be applied to the cap itself,-since theshaft is latched to the cap.

Alternatively, the cartridge may have a mechanism incorporated thereinwhereby the force applied to the flange, operates alternately to latchthe servomechanism in the operating position thereof, and to release theservomechanism from the operating position thereof. In the sameconnection, moreover, the alternate action mechanism may be slidablyengaged on the shaft; between the flange and the cap, and the cap may beyi'eldably biased in the direction of reciprocation, relatively outwardof the cartridge, so that the capis shifted between alternate positionsrelatively inward and outward of the cartridge, when the servomechanismis latched in and released from the operating posi tion thereof. infact, the bias may be applied to the shaft itself, since the cap islatched to the shaft.

For the detailsof a latch and unlatch mechanism which may be employedwith the servomechanism in a keyboard assembly of two or morecartridges, see U.S. Pat. No. 3,249,705. For the details of an alternateaction mechanism which may be employed with the servomechanism, see US.Pat. No. 3,402,379.

Preferably, each servomechanism is mounted in a multi-block base inwhich the blocks are tandemly arranged so that a block can be added toor deleted therefrom for purposes of converting the servomechanism toone effect from another.

In the presentlypreferred embodiments of the invention, moreover, theservomechanism includes an intermediate actuator which is interposedbetween the shaft and the operating unit, and operable to actuate theunit while providing a degree of overtravel for the shaft in theoperating stroke thereof. The actuator comprises a flap that ispivotallymounted about an axis which is transverse to and spaced fromthe operating means of the unit, and which is operable against thebiasing element which is interposed therebetween. It also comprises aU-shaped spring member which is pivotably mounted about the same axis,and cooperatively engaged with the flap to assume a normally stoppedposition between the shaft and the flap, whereby the shaft operates theflap, and thus the operating means of the unit, by compressing the legsof the spring member relatively toward one another, to pivot the flapagainst the bias of the element therebetween.

Once the cap is unlatched from the shaft, it is removable to a positionoutside of the cartridge. in this position, however, the cap is tetheredto the cartridge, so as to remain attached thereto.

in the presently preferred embodiments of the invention, moreover, thetether and the cap are disengageable from one another in the relativelyremoved position of the cup. The cap has an elongated groove in the basethereof, which opens into a foyer at one end thereof, and'the tethercomprises a U-shaped member, the legs of which are flexible in relationto one another, and equipped. with outturned flanges at the ends thereofwhich engage in the foyer of the cap, through the opening thereto fromthe groove. Preferably, the base of the cap is slidably engageable withthe open end of the cartridge, the groove is disposed in one of thosesidewalls of the base which slidably engage with the cartridge, and thetether is adapted to nest in the groove when the cap is so engaged inthe cartridge.

Where the cap is illuminated, the mounting base in the cartridgeincludes an electrical contact assembly through which the lamps of thecaps are energized when the cap is inserted in the cartridge.Preferably,

the baseis multiblocked and the blocks are tandemly arranged, asindicated, and the assembly includes a printed circuit board which isreplaceably clamped between a pair of blocks, and equipped with an arrayof contact points on the printed face thereof, as well as an array ofcontact prongs which are attached to the board along one edge thereof,andextend to the rear of the face through the base, in a correspondingnumber of slits for the same in the base. The cap is electricallyinterconnected with the contact points, in the inserted conditionthereof, and in order to standardize the base,

while allowing for variable electrical arrangements in the cap, theboard is interchanged for another board having differing circuitryinterconnected between the contact points and the points of attachmentof the prongs along the one edge thereof.

The cap also has variable partitioning between the lamps thereof,whereby other variations can also be obtained, if desired.

BRIEF DESCRIPTION OF THE DRAWINGS These features will be betterunderstood by reference to the accompanying drawings which illustratecertain of the preferred embodiments of the invention.

In the drawings,

FIG. 1 is a part schematic, part cutaway perspective view of a keyboardassembly incorporating features of the invention;

FIG. 2 is a part cross-sectional view of one cartridge in theassembly,with the latch mechanism thereof rotated 45 with respect to itsnormal condition in FIG. 8, and illustrated in the engaged conditionthereof;

FIG. 3 is another such part cross-sectional view, illustrating the latchmechanism in the disengaged condition thereof;

FIG. 4 is a larger-scale, part cross-sectionalview of the latchmechanism, when the mechanism is in the engaged condition thereof;

FIG. 5 is a part perspective view of the latch mechanism in thiscondition;

FIG. 6 is a view similar to thatof FIG. 4, when the latch mechanism isin the disengaged condition thereof;

FIG. 7 is a view similar to that of FIG. 5, when the latch mechanismis'in the disengaged condition thereof;

FIG. 8 is a cross-sectional view of the cartridge along the line 88 ofFIG. 2;

FIG. 9 is a part cross-sectional view of the tethering mechanism in thecartridge;

FIG. 10 is a cross-sectional view of the cartridge at the point of theprinted circuit board therein; and

FIG. 11 is a part cross-sectional view of the cartridge when theservomechanism therein is converted to a different effect.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring firstly to FIGS.l-10, it will be seen that the keyboard 2 comprises threedistinct-cartridge units 4 which are assembled in juxtaposition to oneanother and pinned together-cross-wise of the assembly by a pair of rods6 which are passed through a series of transversely aligned holes 8 inthe rear end portions of the cartridges. Each cartridge 4 comprises anopenended tubular metal sheath 10 which is square in cross section andsized to house a mounting base 12 and the various operating componentsof the unit. The mounting base 12 is assembled from three irregularlysized and shaped, hollow-bore plastic blocks 14', 14" and 14" which aretandemly inserted and secured within the rear end portion of the sheath10. The operating components include a triad of transversely apertured,switch modules 16 which are mounted in the rearmost block 14", and aplunger-operated servomechanism 18 which is mounted in the forwardmostand intermediate blocks 14' and 14", to actuate the spring-loadedcontact buttons 20 of the modules 16. The operating components alsoinclude a multi-pronged electrical contact assembly 22 which is mountedin the base 12 to energize the lamps 24 of an illuminated pushbutton cap26 which is insertable in the forward end portion or vestibule 28 of thesheath 10, for use in operating the switch assembly 16 through themedium of the servomechanism 18. The contact assembly 22 is replaceablystructured and mounted so that the lamps 24 can be energized in two ormore variable combinations of the same. The cap 26 is releasable fromthe sheath when desired, as for example, when it is necessary to replacethe lamps. In the inserted condition, the cap is telescopically engagedwith the plunger 30 of the servomechanism, and is operable toreciprocate the plunger through the actuating stroke thereof, when aforce is applied to the cap in the direction relatively inward of thesheath 10. In addition, the cap is releasably latched to the of plunger,so that should the cartridge experience a shock force of limitedduration and extent, the force will not separate the cap from thecartridge in the I direction relatively outward of the sheath. Themechanism 32 for this purpose, may be overridden however, by a-greaterforce such as a finger pull, when it is desired to release the cap fromthe cartridge.

In the released condition, the cap is not freed from the cartridgealtogether, however, in that the cartridge also includes an elongatedtether 33 by which the cap is leashed to the sheath, even after it hasassumed a position relatively outside thereof. See FIG. 1. On the otherhand, when desired, the tether may be disconnected from the cap, or viceversa, to free the cap from the cartridge, when the cap is in thiscondition.

The operating components of the respective cartridges also include meanswhereby the operating stroke of the servomechanism 18 of one cartridge,results in the plunger 30 of that mechanism being latched in theoperating position thereof, while the plunger 30 in the servomechanism18 of one of the other cartridges, is released from the operatingposition thereof. This effect is produced by a latch and unlatchmechanism 34 which is similar to that disclosed in the aforementionedpatent, and which is disposed crosswise of the keyboard, as an operatingcomponent which is common to all of the cartridges.

These various components and features will be better understood by themore detailed discussion of the same which follows hereafter.

Referring firstly to FIGS. l-3 in particular, it will be seen' that thesidewalls 10' of each sheath have pairs of spaced vertically alignedtabs 36 thereon, which are cut and bent inwardly therefrom, adjacent thelongitudinal centers of the same. The righthand sidewall also has a pairof spaced longitudinally aligned staples 38 thereon, that are bentinwardly therefrom, to either side of the pair of tabs 36 thereon. Inaddition, the lower rear end edge portion of each sheath is removed toform a step 40 on either side thereof, and the holes 8 are providedthereabove, to accommodate the connecting rods 6, as indicated; whereasthe latch and unlatch mechanism 34 is accommodated in a larger L- shapedhole 44 which is disposed more forwardly in each sidewall 10 of eachsheath, that is oriented inwardly of the keyboard when the cartridgesare assembled.

The bore 46 of the forwardmost mounting block 14 is deeply counterboredfrom the rear, and to a lesser extent from the front, to form relativelydeeply inset and shallow shoulders 48 and 50, respectively, therein. 8

Moreover, the deeply inset shoulder 48 is rabbetted twice to form to twoprogressively narrower shoulders 52 and 54 therein. symmetricallyarrayed about the bore 46 are six smaller bores 56, three above andthree below, which are also deeply counterbored from the rear to formdeeply inset shoulders 58 therein. The rear end face of the block 14' isslightly relieved about the full array of bores 56, yet short of theoutline of the block, so as to leave a square-shaped recess 60 in theface, which is surrounded by a raised peripheral rim. And lastly, theforward edges of the rightand left-hand sidewalls of the block, aredeeply rabbetted, so as to form shoulders 62 to either side of theblock, which abut the tabs 36 in the sheath when the base is insertedtherein. The right-hand sidewall also has a deep,

longitudinally-extending groove 64 therein, which opens to the front ofthe block, but terminates short of the rear end face thereof. The groove64 in turn has a narrower countergroove 66 down the center thereof,which is cut through the terminal wall 68 of the groove 64, to the rearend face of the block.

The intermediate block 14" is considerably reduced in thickness,longitudinally of the sheath, and has a deeply removed foyer 70 formedin the rear end face thereof, which opens to the front through the bore72 therein, and is overhung by a corbeled mantel 74, the corbel 76 ofwhich has a pair of spaced, rearwardly directed indexing buttons 78outstanding thereon. The deck 80 of the foyer is slotted, and inaddition, has a step 82 thereon coincident with the face of the corbel76.

The rearmost block 14' has the greatest longitudinal extent, althoughlike the intermediate block 14", most of it is removed, in this instanceto form a deeply inset vestibule 84 in the rear end thereof, thesidewalls of which have transversely aligned holes 88 in the upper frontcorners of the same, the insides of which corners have lands 90 formedthereon, which are slotted at the rear edges thereof, the slots 92terminating in coincidence with the holes 88. The sidewalls of thevestibule also have pairs of notches 94 in the rear edges thereof, andthe deck 96 of the vestibule has right angular shoulders 97 outstandingon the lower rear end edge portion thereof, and is slotted to registerwith the slots 98 in the intermediate block 14", although in the case ofthe rearmostblock, the slots 100 terminate short of the rear end facethereof, to form a grated end wall 101 having six horizontally disposedslits 102 therein. The vestibule 84 opens to the front of the blockthrough the bore 104 therein, which has a countersink 106 formedthereabout, in the front face of the block.

The contact assembly 22 comprises a centrally apertured printed circuitboard 108 which has an array of contact studs 110 outstanding thereon,corresponding in location to the array of bores 56 in the forwardmostmounting block 14. An equal number of L-shaped, end-apertured prongs 112is soldered to the lower edge portion of the board, to extend onperpendiculars to the rear of the board at sufficient length to passthrough and beyond the slots 98 and 100, and the grated end wall 101 ofthe base. The circuitry 114 of the board is interposed between the studs110 and the solder connections 116 of the prongs 112, and may beinterconnected in various arrangements from one cartridge to another,depending on such considerations as the number and arrangement of lampsin the caps, and the num-,

8 her of commons among the prongs from one contact assembly to another.In each cartridge, the printed circuit board 108 is clamped between theforwardmost and intermediate blocks 14' and 14", and is housed withinthe recess 60 in the rear end face of the forwardmost block, with prongs112 thereof extending rearwardly through the slots 98 and 100, and thenthe grated end wall 101 of the base. Contact is made between the lamps24 of the cap and the studs of the printed circuit board, through themedium of six hollow, flanged, spring-loaded contact posts 118 which arecarried in the bores 56 of the forwardmost block, and loaded in theforwarddirection, against the shoulders 58, under the bias of an equalnumber of coiled springs 120 which are caged within the posts about thestuds 110.

Midway the length of the plunger 30 of the servomechanism 18, there is athick radial flange 122 on the shank 124 of the same, the forward endface 126 of which is chamfered in a sharp taper, and the rear end face128 of which is chamfered in a more gentle taper. The'plunger 30also hasa deeply inset bore 130 in the forward end thereof, and is equipped witha pair of re tainer rings 132 and 134 which are slidably engaged on theforward end portion of the shank 124, with a coiled spring 136 cagedtherebetween. The opposing faces of the rings are rabbetted to formshoulders for seating the spring, and the more forwardly disposed ring132 is retained on the plunger by peening over the tip 138 of the same,whereas the more rearwardly disposed ring 134 abuts the sharply taperedend face 126 of the flange 122 on the plunger, after the flange 122 isreceived in a recess. 140 counterbored in the rear end face of the ring134.

Telescoped in the bore 130 of the plunger is an elongated shaft 142which has a wide circumferential groove 144in thetipped forward endportion thereof, and a narrow circumferential groove 146 in the waistportion thereof. An E-shaped open-sided retainer clip 148 is engaged inthe narrower groove 146, and an elastromeric washer 150 and a metalwasher 152, are slipped over the rear and forward end portions of theshaft, respectively, in abutment with the clip 148.

The servomechanism 18 also comprisesan intermediate, flap-like actuator154, which is interposed between the plunger 30 and the switch modules16, to operate the buttons 20 of the modules under the impetus of theplunger, and at the same time to provide for a degree of overtravel onthe part of the plunger in the operating stroke. The actuator 154consists of a yoke-like sheet metal flap .156 which is pivoted to atrunnion pin 158 and has an L-shaped extension 160 thereon, in whichthere is a slot 162 to receive a U-shaped loop 164 formed in a coiledspring 166 which is doublewound about the pin 158, to either side of theloop 164, and restrained under tension by engaging its ends against thetransom 168 of the flap. I

Consistent with the disclosure of US. Pat. No. 3,249,705 the latch andunlatch mechanism 34 for the plunger comprises an elongated backup plate170 which is adapted to extend the full width of the keyboard, and hassets of upper and lower transversely aligned holes 172-and 174therethrough, the lower 172 of which are counter-sunk and chamfered atthe forward ends thereof, and the upper 174 of which are disposed inpairs to either side of the lower holes 172, and adapted to mate withthe buttons 78 on the intermediate block, for purposes of fixing theplate 170 in the foyer 70 of the block, between the step 82 and thecorbel 76 of the block, and the bulkhead 176 of the rearmost block14"..The latch and unlatch mechanism 34 also comprises a spring-loadedlatch plate 178 which corresponds to that seen at 30 in FIG. of thepatent, and which is characterized with holes 180 at spaced intervalsthat are oversized with respect to the flange 122 of the plunger, tofunction in the manner of the holes 30b in the patent. lnterposedbetween the two plates 170 and 178, is a pair of end-notched lockoutplates 182, the end notches of which are V-shaped in cross section andsized to cooperate with the flange 122 on the plunger, in the manner ofthe plates 26 and 28 in the patent, there being a plate 182 to eitherside of the plunger, as in the patent.

The tethering mechanism 33 comprises a length of wire 184 which isstepped at the middle,and reentrantly bent at either end, to form aretainer loop for another length of wire 186 which is hooked thereaboutwithin the cartridge. The latter piece of wire 186 is essentiallyU-shaped in configuration, and has outturned feet 188 on the endsthereof, for engaging the wire 186 on the cap, as shall be explained. I

In assembling the cartridge, the mounting base 12 is inserted in therear end portion of the sheath until the shoulders 62 of the forwardmostblock abut the tabs on the sidewalls of the sheath, and the shoulders 97of the rearmost block engage in the steps 40 at the rear of the sheath.Then the sidewalls 10 are pinched in, about the holes 8, in preparationfor the rods 6 being added to the same through the notches 94, as thekeyboard is assembled-from the three cartridges. Prior to insertion ofthe base, however, the contact posts 118 are loaded into the bores 56 ofthe forwardmost block, and the circuit board 108 is interposedbetween-the forwardmost and intermediate blocks, with the springs 120 ofthe posts surrounding the studs 110 of the board, and with the prongs112 of the board projecting to the rear through the slots 98 and 100,and the grated end wall 101 of the base. Also, the reentrant tips of thetethering loop 184 are engaged in the staples 38 of the sheath, and asthe base is added, the body of the loop 184 is engaged in thecountergroove 66 of the block 14, with the tethering wire 186 retainedthereon. The plunger 30 is slidably engaged in the bore 46, 72, 104 ofthe base, and the clip and washer assembly 148, 150, 152 on the shaft142 of the same, is nested in the recess defined by the progressivelynarrower shoulders 52 and 54 of the forwardmost block, so as to restrainthe shaft against movement in both the sidewise and forward directionsthereof. Moreover, the rings 132 and 134 on the shank 124 of the plungerare interposed between the surrounding shoulder 48 of the bore 46, andthe bulkhead 190 of the intermediate block 14", to provide the necessaryloading on the plunger. Meanwhile, the flanged rear end portion ofthe'plunger is extended into and through the foyer 70 of theintermediate block, and the plates 170, 178 and 182 of the latch andunlatching assembly are arranged transversely thereof, from cartridge tocartridge, through the openings 44 in the sheathes. See FIG. 1. Also,the trunnion pin 158 of the flap actuator is inserted through the slots92 in the lands 90 on the sidewalls of the rearmost block, and isengaged in the holes 88; after which the switch modules 16 are insertedbehind the actuator, and are pinned to the cartridge in the'vestibule 84of the block, and 21 coiled spring 192 engaged about each of the buttons20 I of the same, to bias the actuator into the stopped position of FIG.2.

The cap 26 has a hollow base 194 which is essentially square-shaped inoutline, though chamfered at the corners, and which is sized to beslidably received in the vestibule 28 of the cartridge. The rear end ofthe base has a spider-like cross section, providing four symmetricallyarrayed sockets 196 for the lamps 24 of the cap. The lamps areinserted-into the sockets from the rear, and project into a foyer 198 atthe front of the cap. The foyer is selectively partitioned by one ormore platelike dividers 200, which are slidably engaged in grooves 202in the forward end edges of the webbing 204 of the spider, as well as ingrooves 206 in the bottom and sidewalls of the foyer 198. The foyer isalso defined in part by a square-shaped ferrule 208 which is engaged andsecured about the forward end portion of the base, in a rabbet 210adapted to receive the same, and which has a set of lenses 212 therein,that present colorbackgrounded intelligence to viewers of the cap, theintelligence being coordinated with the combination of lamps in usetherebehind, due to the presence of the dividers 200 between the lamps.

When the cap is inserted in the vestibule 28 of the cartridge, the posts118' at the four corners of the array of bores 56 in the base 12,contact the buttons 214 of the lamps. The two remaining posts 118"contact a pair of metal studs 216 which are fixed on the verticalwebbing 204 of the spider, and which are equipped with bent-over teeflanges 218, the bent-over arms of which make contact with the shells220 of the lamps, to ground the same through the posts 118".

The. cap 26 is also equipped with other features which relate to thelatching and tethering of the same in the cartridge. The body of thespider projects to the rear of the base 194, at the confluence of thewebbing 204, and a stepped embossment 222 is formed thereon, the bore224 of which opens to the front through the spider. The bore 224 iscounterbored from the front, moreover, to form a deeply inset shoulder226 therein, adjacent the tip of the embossment; and there is also asquare-sectioned countersink 228 at the front of the bore 224, whichforms a seat for a square-outlined washer230that is bonded or otherwisesecured in the countersink 228 behind the dividers 200. To the rear ofthe washer, that is, between the seat 228 and the shoulder 226, the bore224 is'enlarged to an intermediate depth, in the same section as thewasher, and pairs of oppositely disposed ramps 232 are formed onoppositely disposed walls 234 of the enlargement 236, with inclines thattaper relatively toward the countersink 228, and inwardly of the bore224. See FIGS. 5 and 7. The ramps 232 provide camingsurfaces for anapertured U-shaped spring clip 238 which is loaded within the bore 224behind the washer 230, and biased into engagement with the washer, by acoiled spring 240 which is interposed between the apertured bightportion 242 of the clip and the shoulder 226 of the bore. The leaves ofthe clip 238 are oriented crosswise of the ramps 232 and have laterallyprojecting flanges 244 at the tips thereof, which are adapted to' rideon the ramps, to either side of the clip.

When the cap is inserted in the vestibule 28 of the cartridge, the shaft142 of the plunger telescopes within the bore 224 of the cap. The spring240 and the aperture 246in the bight portion 242 of the clip, are sizedl 1 to enable the shaft to pass therethrough, and the washer 230 is alsosized to receive the head 248 of the shaft. But the gap between the tips244 of the clip, is undersized with respect to the shaft, so that whenthe head 248 of the shaft enters the bore 224 through the mouth 250thereof, it readilypenetrates the spring 240 and the clip 238, but inreaching the washer 230 separates the tips 244, until the tips coincidewith the groove 144 at the rear of the head 248. At this point, the tipssnap into engagement with the groove, and latch the cap 26 to the shaft142 when they are abutted against the head 248 at the forward end of thegroove [44, under the bias of the spring 240. The bias is suffrcient,moreover, to withstand shocks of the magnitude which the cartridge maybe expected to experience in periods of normal use and abuse.

On the other hand, when desired, the cap may be released from the shaft142 by overcoming the bias of the spring 240, such as with a finger pulloutward of the cartridge. In such a case, the cap undergoes displacementrelative to the shaft, and the ramps 232 cause the flanged tips 244 ofthe clip to separate, as the ramps undergo displacement forwardly of thecartridge. Ultimately, after a short period of lost motion, the tips aredisengaged from the groove 144, and the cap is freed from the shaft 142,and vice versa, for release from the cartridge to the position ofFIG. 1. At the same time, the spring 240 reengages the clip with thewasher 230, so that'the cycle can berepeated when the cap is returned tothe vestibule 28 of the cartridge.

Looking again to FIG. 1, it will be seen that the base 194 of the capalso has an inset V-sectioned groove 252 in the near sidewall thereof,that is, in the sidewall thereof corresponding to the side of the sheathon which the tether 33 is located. The groove 252 extends forwardly fromthe rear end of the base, and terminates at a point coinciding witth theforwardly oriented face of the spider, so as to open into the foyer 198of the cap. The tethering wire 186 is attached to the cap by orientingthe feet 188 of the same lengthwise of the groove 252, inserting thefoot on one leg of the wire into the foyer through the opening 254thereto and thereafter flexing the other leg crosswise of the. firstleg, until the foot 188 of it is juxtaposed with the foot of the firstleg, and the wire and the cap can be engaged by swivelling one inrelation to the other, to enable the foot of this other leg to enter theopening 254 as it returns to its normal position under the flexureinherent in the wire.

To disengage the two, the process is reversed.

FIG. 11 illustrates the manner in which the cartridge may be modified toserve as an alternate action device of the type shown in US. Pat. No.3,402,379. The intermediate block 14" of the mounting base 12 iseliminated, as is theplunger 30 and the clip and ring assembly 148, 150,152 on the shaft 142 of the servomechanism. Instead, the shaft 142 (FIG.11) is modified to carry a circumferential enlargement 256 on the rearend thereof, and a jaw clutch mechanism 258 such as that seen in FIG. 3of the patent, is slidably engaged on the shaft 142', between theenlargement 256 and the shoulders 48,52, 54 of the forwardmost block.Also, the female clutch member 260 has an outturned flange 262 on therear end thereof, which is interengaged between the forwardmost andrearmost blocks 14 and 14" in the countersink 106 of the latter block.The clutch release member is seen at 264, and operates on J g a I3,824,363

the male clutch member 266, alternately to actuate and release theintermediate mechanism 154 which corresponds to the caged spring unit 46in the patent.

The alternate action device of FIG. 11 can be converted into a momentaryaction device, simply by eliminating the fillet portions 268 between theribs 270 of the female member 260 so that the device returns to thenormal position on each push of the cap. In this way, for manufacturingpurposes, only the mold of the female member 260 needs to be changed.

What is claimed is:

1. In combination, a relatively reciprocable member, and a releasablelatch mechanism for the member, comprising means defining a stop aboutthe path of reciprocation of the member, a latch element which isreciprocable in parallel with the member, but independently thereof, andwhich is yieldably biased in a direction lengthwise of the path ofreciprocation of the member, into engagement with the stop, as well asyieldably biased in a direction transverse of the path, to assume aposition thereon, detent means which are operable to interengage thelatch element and the member, when the member is reciprocated againstthe bias on theelement in the direction transverse of the path,

and latch release means which are operable to disengage the latchelement and the member, when the member and the element are conjointlyreciprocated against the bias on the latch element in the directionlengthwise of the path.

2. The combination according to claim 1 wherein the latch element has aflexible portion thereof which is cantilevered into the path of themember, from a point outside thereof, and which is deflectable by themember, relatively out of the path, when the member is reciprocated inthe direction of the bias on the element, lengthwise of the path, butwhich relaxes into engagement with the member, to reciprocate inconjunction therewith, when the member is reciprocated in the directionopposed to the bias on the element, lengthwise of the path.

3. The combination according to claim 2 wherein the latch release meansincludes meanswhich are operable to redeflect the portion of theelement, relatively out of the path, after the element has undergone aperiod of lost motion, in the direction opposed to the bias thereon,lengthwise of the path.

4. The combination according to claim 3 wherein the member is elongatedin the directions of reciprocation, and the flexible portion of theelement takes the form of a leaf spring which is cantilevered from acarrier element that is coaxially disposed with the member, about thepath of reciprocation thereof, and slidably engageable by the member inthe course of reciprocation thereof.

5. The combination according to claim 4 wherein the detent means takesthe form of a recess in the member, into which the spring relaxes fromthe deflected condition thereof. I

6. The combination according to claim 5 wherein the latch release meanstakes the form of a bearing surface which is inclined to the path ofreciprocation of the member, and slidably engageable with the spring, todeflect the spring relatively out of the recess, after the carrierelement has undergone a period of lost motion, in the direction opposedto the bias thereon, lengthwise of the path.

7. The combination according to claim 6 wherein the membertelescopically engages in a socket which has an annular shouldertherein, about the path of the member, and pairs of oppositely disposedramps therein, which are interposed between the shoulder and the mouthof the socket, on opposite sides of the path, and inclined toward theopening within the shoulder.

8. The combination according to claim 7 wherein the carrier elementtakes the form of a ring which is disposed in the socket, coaXially withthe path of the member, and has a pair of codirected leaf springs ondiametrically opposite sides thereof, which together with the ring forma U-shaped spring clip, within which the member is slidably engageablein the course of reciprocation thereof.

9. The combination according to claim 8 wherein the member has a flangethereon, and the tips of the leaves of the clip engage in acircumferential groove in the member, when the flange engages a stopadjacent the mouth of the socket; and wherein the leaves have flangesthereon which slidably engage on the ramps, so as to deflect the leavesfrom one another, when the clip is reciprocated against the bias of acoiled spring which is interposed in the socket, between the ring and asecond annular shoulder therein, that is disposed adjacent the mouth ofthe socket and opposed in orientation to the first mentioned shoulder.

10. In combination, an open-ended cartridge having a latch membertherein, and a cap which is reciprocably guided in the open end of thecartridge to engage and disengage. the member, said cap defining a stopabout the path of engagement and disengagement -of the member, a latchelement which is reciprocable in parallel with the cap, as well asindependently thereof, and which is yieldably biased in a directionlengthwise of the path ofengagement and disengagementof the member, intoengagement with the stop, as well as yieldably biased in a directiontransverse of the path, to assume a position thereon, detent means whichare operable to interengage the latch element and the member, when thecap is reciprocated in relation to the member so as to engage the memberwith the cap against the bias on the element in the direction transverseof the path, and latch release means which are operable to disengage thelatch element and the member, when the cap is reciprocated in relationto the member and the element so as'to disengage the member from the capagainst the bias on the latch element in the direction lengthwise of thepath.

11. The combination according to claim 10 wherein the detent means isdisposed on the member.

12. The combination according to claim 10 wherein the latch member takesthe form of a shaft incorporated in a servomechanism for an operatingunit which is mounted in thecartridge.

13. The combination according to claim 12 wherein the shaft isreciprocable and has a flange thereon, so that the operating unit can beactuated by unidirectional forces applied to the flange, through thecap, in the direction of reciprocation of the shaft, relatively inwardof the cartridge. I

14. The combination according to claim 13 wherein the cartridge is oneof a keyboard of the same, and the keyboard has a mechanism incorporatedtherein whereby the force applied to the flange on the shaft of onecartridge, operates to latch the respective servomechanism in theoperating position thereof, while si- 14 multaneously releasing theservomechanism of another cartridge, from the operating positionthereof.

15. The combination according to claim 14 wherein the shaft in eachcartridge is telescopically engaged with the respective servomechanismtherein, and is yieldably biased in the direction of reciprocation,relatively outward of the cartridge, so that the cap is returned to thenormal position thereof, each time a force is applied to the same.

16. The-combination according to claim 15 wherein the bias on the shaftis applied through the cap.

17. The combination according to claim 13 wherein the cartridge has amechanism incorporated therein whereby the force applied to the flange,operates alternately to latch the servomechanism in the operatingposition thereof, and to release the servomechanism from the operatingposition thereof.

18. The combination according to claim 17 wherein the aforesaidalternate action mechanism is slidably engaged on the shaft, between theflange and the cap, and the cap is yieldably biased in the direction ofreciprocation, relatively outward of the cartridge, so that the cap isshifted between alternate positions relatively inward and outward of thecartridge, when the servomechanism is latched in and released from theoperating position thereof.

19. The combination according to claim 18 wherein the bias on the cap isapplied through the shaft.

20. The combination according to claim 12 wherein the servomechanism ismounted in a multiblock base in which the blocks are tandemly arrangedso that a block can be added to or deleted therefrom for purposes ofconverting the servomechanism to one of several variable effects fromanother.

21. The combination according-to claim 12 wherein the servomechanismincludesan intermediate actuator which is interposed between the shaftand the operating unit, and operable to actuate the unit providing adegree of overtravel for the shaft in the operating stroke thereof. I

22. The combination according to claim 21 wherein the actuator comprisesa flap which is pivotally mounted about an axis that istransverse to andspaced from the operating means of the unit, and which is operableagainst a biasing element that is interposed therebetween.

23. The combination according to claim 22 wherein the actuator alsocomprises a U-shaped spring member which is pivotally mounted about thesame axis as the flap, and cooperatively engaged with the flap to assumea normally stopped position between the shaft and the flap, whereby theshaft operates the flap, and thus the operating means of the unit, bycompressing the legs of the spring member relatively toward one another,to pivot the flap against the bias of the element therebetween.

24. The combination according to claim 10 wherein the cap is removableto a position outside of the cartridge, when it is unlatched from themember.

25. The combination according to claim 24 wherein the cap is tethered tothe cartridge, in the relatively removed position thereof, so as toremain attached to the cartridge.

26. The combination according to claim 25 wherein the tether and thecapare disengageable from one another in the relatively removed position ofthecap.

, gage in the foyer of the cap, through the opening thereto from thegroove.

28. The combination according to claim 27 wherein the base of the cap isslidably engageable with the open end of the cartridge, the groove isdisposed in one of those sidewalls of the base which slidably engagewith the cartridge, and the tether is adapted to nest in the groove whenthe cap is so engaged in the cartridge.

29. The combination according to claim 10 wherein the cap isilluminated, and there is a mounting base in the cartridge including anelectrical contact assembly through which the lamps of the cap areenergized when the cap is inserted in the cartridge.

30. The combination according to claim 29 wherein the base ismultiblocked and the blocks are tandemly arranged, and the assemblyincludes a' printed circuit board which is replaceably clamped between apair of blocks, and equipped with an array of contact points on theprinted face thereof, as well as an array of contact prongs which areattached to the board along one edge thereof, and extend to the rear ofthe face through the base, in a corresponding number of slits for thesame in the base.

31. The combination according to claim 30 wherein the cap has variablepartitioning between the lamps thereof.

32. in combination, a relatively reciprocable member, and a releasablelatch mechanism for the member, comprising means defining a stop aboutthepath of reciprocation of the member, a latch element which isreciprocable in parallel with the member, but independently thereof, andwhich is yieldably biased in a direction lengthwise of the path ofreciprocation of the member, into engagement with the stop, as well asyieldably biased in a direction transverse of the path, to assume aposition thereon, detent means which are operable to interengage thelatch element and the member, when the member is reciprocated againstthe bias on the element in the direction transverse of the path,

and latch release means which are operable to disengage the latchelement and the member, when the member is reciprocated against the biason the latch e1- ement in the direction lengthwise of the path, saidlatch element having a flexible portion thereof which is cantileveredinto the path of the member, from a point outside thereof, and which isdeflectible by the member, relatively out of the path, when the memberis reciprocated in the direction of the biason the element, lengthwiseof the path, but which relaxes into engagement with the member, toreciprocate in conjunction therewith, when the member is reciprocated inthe direction opposed to the bias on the element, lengthwise of thepath, and said latch release means including means which are operable toredeflect the portion of the element, relatively out of the path, afterthe element has undergone a period of lost motion, in the directionopposed to the bias thereon, lengthwise of the path.

33. In combination, an open-ended cartridge having a latch membertherein, and a cap which is slidably guided in the open end of thecartridge to engage and disengage the member, said cap defining a stopabout the path of engagement and disengagement of the member, a latchelement which is reciprocable in parallel with the cap, as well asindependently thereof, and which is yieldably biased in a directionlengthwise of the path of engagement and disengagement of the member,into engagement with the stop, as well as yieldably biased in adirection transverse of the path, to assume a position thereon, detentmeans which are operable to interengage the latch element and themember, when the member is engaged with the cap against the bias on theelement in the direction transverse of the path, and latch release meanswhich are operable to disengage the latch element and the member, whenthe member is disengaged from the cap against the bias on the latchelement in the direction lengthwise of the path, said latch membertaking the formof a shaft incorporated in a servomechanism for anoperating unit which is mounted in the cartridge, and said shaft beingreciprocable and having a flange thereon, so that the operating unit canbe actuated by-uni-directional forces applied to the flange, through thecap, in the direction ofreciprocation of the shaft, relatively inward ofthe cartridge, and said cartridge having a mechanism incorporatedtherein whereby the force applied to the flange, operatesalternately tolatch the servomechanism in the operating position thereof, and torelease the servomechanism from t the operating position thereof, saidalternate action mechanism being slidably engaged on the shaft, betweenthe flange and the cap, and the cap being yieldably biased in thedirection of reciprocation, relatively outward of the cartridge, so

- that the cap is shifted between alternate positions relatively inwardand outward of the cartridge, when the servomechanism is latched in andreleased from the operating position thereof.

34. In combination, an open-ended cartridge having a latch membertherein, and a cap which is slidably guided in the open end of thecartridge to engage and disengage the member, said cap defining a stopabout the path of engagement and disengagement of the member, a latchelement which is reciprocable in parallel with the cap, as well asindependently thereof, and which is yieldably biased in a directionlengthwise of the path of engagement and disengagement of the member,into engagement with the stop, as well as yieldably biased in adirection transverse of the path, to assume a position thereon, detentmeans which are operable to interengage the latch element and themember, when the member is engaged with the cap against the bias on theelement in the direction transverse of the path, and latchrelease meanswhich are operable to disengage the latch element and the member, whenthe member is disengaged from the cap against the bias on the latchelement in the direction lengthwise of the path, said latch membertaking the form of a shaft incorporated in a servomechanism for anoperating unit which is mounted in the cartridge, and saidservomechanism including an intermediate actuator which is interposedbetween the shaft and the operating unit, and operable to actuate theunit while providing a degree of over-travel for the shaft in theoperating stroke thereof.

1. In combination, a relatively reciprocable member, and a releasablelatch mechanism for tHe member, comprising means defining a stop aboutthe path of reciprocation of the member, a latch element which isreciprocable in parallel with the member, but independently thereof, andwhich is yieldably biased in a direction lengthwise of the path ofreciprocation of the member, into engagement with the stop, as well asyieldably biased in a direction transverse of the path, to assume aposition thereon, detent means which are operable to interengage thelatch element and the member, when the member is reciprocated againstthe bias on the element in the direction transverse of the path, andlatch release means which are operable to disengage the latch elementand the member, when the member and the element are conjointlyreciprocated against the bias on the latch element in the directionlengthwise of the path.
 2. The combination according to claim 1 whereinthe latch element has a flexible portion thereof which is cantileveredinto the path of the member, from a point outside thereof, and which isdeflectable by the member, relatively out of the path, when the memberis reciprocated in the direction of the bias on the element, lengthwiseof the path, but which relaxes into engagement with the member, toreciprocate in conjunction therewith, when the member is reciprocated inthe direction opposed to the bias on the element, lengthwise of thepath.
 3. The combination according to claim 2 wherein the latch releasemeans includes means which are operable to redeflect the portion of theelement, relatively out of the path, after the element has undergone aperiod of lost motion, in the direction opposed to the bias thereon,lengthwise of the path.
 4. The combination according to claim 3 whereinthe member is elongated in the directions of reciprocation, and theflexible portion of the element takes the form of a leaf spring which iscantilevered from a carrier element that is coaxially disposed with themember, about the path of reciprocation thereof, and slidably engageableby the member in the course of reciprocation thereof.
 5. The combinationaccording to claim 4 wherein the detent means takes the form of a recessin the member, into which the spring relaxes from the deflectedcondition thereof.
 6. The combination according to claim 5 wherein thelatch release means takes the form of a bearing surface which isinclined to the path of reciprocation of the member, and slidablyengageable with the spring, to deflect the spring relatively out of therecess, after the carrier element has undergone a period of lost motion,in the direction opposed to the bias thereon, lengthwise of the path. 7.The combination according to claim 6 wherein the member telescopicallyengages in a socket which has an annular shoulder therein, about thepath of the member, and pairs of oppositely disposed ramps therein,which are interposed between the shoulder and the mouth of the socket,on opposite sides of the path, and inclined toward the opening withinthe shoulder.
 8. The combination according to claim 7 wherein thecarrier element takes the form of a ring which is disposed in thesocket, coaxially with the path of the member, and has a pair ofcodirected leaf springs on diametrically opposite sides thereof, whichtogether with the ring form a U-shaped spring clip, within which themember is slidably engageable in the course of reciprocation thereof. 9.The combination according to claim 8 wherein the member has a flangethereon, and the tips of the leaves of the clip engage in acircumferential groove in the member, when the flange engages a stopadjacent the mouth of the socket; and wherein the leaves have flangesthereon which slidably engage on the ramps, so as to deflect the leavesfrom one another, when the clip is reciprocated against the bias of acoiled spring which is interposed in the socket, between the ring and asecond annular shoulder therein, that is disposed adjacent the mouth ofthe socket and opposed in orientation to the first mentioned shoulder.10. In combination, an open-ended cartridge having a latch membertherein, and a cap which is reciprocably guided in the open end of thecartridge to engage and disengage the member, said cap defining a stopabout the path of engagement and disengagement of the member, a latchelement which is reciprocable in parallel with the cap, as well asindependently thereof, and which is yieldably biased in a directionlengthwise of the path of engagement and disengagement of the member,into engagement with the stop, as well as yieldably biased in adirection transverse of the path, to assume a position thereon, detentmeans which are operable to interengage the latch element and themember, when the cap is reciprocated in relation to the member so as toengage the member with the cap against the bias on the element in thedirection transverse of the path, and latch release means which areoperable to disengage the latch element and the member, when the cap isreciprocated in relation to the member and the element so as todisengage the member from the cap against the bias on the latch elementin the direction lengthwise of the path.
 11. The combination accordingto claim 10 wherein the detent means is disposed on the member.
 12. Thecombination according to claim 10 wherein the latch member takes theform of a shaft incorporated in a servomechanism for an operating unitwhich is mounted in the cartridge.
 13. The combination according toclaim 12 wherein the shaft is reciprocable and has a flange thereon, sothat the operating unit can be actuated by unidirectional forces appliedto the flange, through the cap, in the direction of reciprocation of theshaft, relatively inward of the cartridge.
 14. The combination accordingto claim 13 wherein the cartridge is one of a keyboard of the same, andthe keyboard has a mechanism incorporated therein whereby the forceapplied to the flange on the shaft of one cartridge, operates to latchthe respective servomechanism in the operating position thereof, whilesimultaneously releasing the servomechanism of another cartridge, fromthe operating position thereof.
 15. The combination according to claim14 wherein the shaft in each cartridge is telescopically engaged withthe respective servomechanism therein, and is yieldably biased in thedirection of reciprocation, relatively outward of the cartridge, so thatthe cap is returned to the normal position thereof, each time a force isapplied to the same.
 16. The combination according to claim 15 whereinthe bias on the shaft is applied through the cap.
 17. The combinationaccording to claim 13 wherein the cartridge has a mechanism incorporatedtherein whereby the force applied to the flange, operates alternately tolatch the servomechanism in the operating position thereof, and torelease the servomechanism from the operating position thereof.
 18. Thecombination according to claim 17 wherein the aforesaid alternate actionmechanism is slidably engaged on the shaft, between the flange and thecap, and the cap is yieldably biased in the direction of reciprocation,relatively outward of the cartridge, so that the cap is shifted betweenalternate positions relatively inward and outward of the cartridge, whenthe servomechanism is latched in and released from the operatingposition thereof.
 19. The combination according to claim 18 wherein thebias on the cap is applied through the shaft.
 20. The combinationaccording to claim 12 wherein the servomechanism is mounted in amultiblock base in which the blocks are tandemly arranged so that ablock can be added to or deleted therefrom for purposes of convertingthe servomechanism to one of several variable effects from another. 21.The combination according to claim 12 wherein the servomechanismincludes an intermediate actuator which is interposed between the shaftand the operating unit, and operable to actuate the unit providing adegree of overtravel for the shaft in the operating stroke thereof. 22.The combination aCcording to claim 21 wherein the actuator comprises aflap which is pivotally mounted about an axis that is transverse to andspaced from the operating means of the unit, and which is operableagainst a biasing element that is interposed therebetween.
 23. Thecombination according to claim 22 wherein the actuator also comprises aU-shaped spring member which is pivotally mounted about the same axis asthe flap, and cooperatively engaged with the flap to assume a normallystopped position between the shaft and the flap, whereby the shaftoperates the flap, and thus the operating means of the unit, bycompressing the legs of the spring member relatively toward one another,to pivot the flap against the bias of the element therebetween.
 24. Thecombination according to claim 10 wherein the cap is removable to aposition outside of the cartridge, when it is unlatched from the member.25. The combination according to claim 24 wherein the cap is tethered tothe cartridge, in the relatively removed position thereof, so as toremain attached to the cartridge.
 26. The combination according to claim25 wherein the tether and the cap are disengageable from one another inthe relatively removed position of the cap.
 27. The combinationaccording to claim 26 wherein the cap has an elongated groove in thebase thereof, which opens into a foyer at one end thereof, and thetether comprises a U-shaped member, the legs of which are flexible inrelation to one another, and equipped with outturned flanges on the endsthereof which engage in the foyer of the cap, through the openingthereto from the groove.
 28. The combination according to claim 27wherein the base of the cap is slidably engageable with the open end ofthe cartridge, the groove is disposed in one of those sidewalls of thebase which slidably engage with the cartridge, and the tether is adaptedto nest in the groove when the cap is so engaged in the cartridge. 29.The combination according to claim 10 wherein the cap is illuminated,and there is a mounting base in the cartridge including an electricalcontact assembly through which the lamps of the cap are energized whenthe cap is inserted in the cartridge.
 30. The combination according toclaim 29 wherein the base is multiblocked and the blocks are tandemlyarranged, and the assembly includes a printed circuit board which isreplaceably clamped between a pair of blocks, and equipped with an arrayof contact points on the printed face thereof, as well as an array ofcontact prongs which are attached to the board along one edge thereof,and extend to the rear of the face through the base, in a correspondingnumber of slits for the same in the base.
 31. The combination accordingto claim 30 wherein the cap has variable partitioning between the lampsthereof.
 32. In combination, a relatively reciprocable member, and areleasable latch mechanism for the member, comprising means defining astop about the path of reciprocation of the member, a latch elementwhich is reciprocable in parallel with the member, but independentlythereof, and which is yieldably biased in a direction lengthwise of thepath of reciprocation of the member, into engagement with the stop, aswell as yieldably biased in a direction transverse of the path, toassume a position thereon, detent means which are operable tointerengage the latch element and the member, when the member isreciprocated against the bias on the element in the direction transverseof the path, and latch release means which are operable to disengage thelatch element and the member, when the member is reciprocated againstthe bias on the latch element in the direction lengthwise of the path,said latch element having a flexible portion thereof which iscantilevered into the path of the member, from a point outside thereof,and which is deflectible by the member, relatively out of the path, whenthe member is reciprocated in the direction of the bias on the element,lengthwise of the path, but which relaxes Into engagement with themember, to reciprocate in conjunction therewith, when the member isreciprocated in the direction opposed to the bias on the element,lengthwise of the path, and said latch release means including meanswhich are operable to redeflect the portion of the element, relativelyout of the path, after the element has undergone a period of lostmotion, in the direction opposed to the bias thereon, lengthwise of thepath.
 33. In combination, an open-ended cartridge having a latch membertherein, and a cap which is slidably guided in the open end of thecartridge to engage and disengage the member, said cap defining a stopabout the path of engagement and disengagement of the member, a latchelement which is reciprocable in parallel with the cap, as well asindependently thereof, and which is yieldably biased in a directionlengthwise of the path of engagement and disengagement of the member,into engagement with the stop, as well as yieldably biased in adirection transverse of the path, to assume a position thereon, detentmeans which are operable to interengage the latch element and themember, when the member is engaged with the cap against the bias on theelement in the direction transverse of the path, and latch release meanswhich are operable to disengage the latch element and the member, whenthe member is disengaged from the cap against the bias on the latchelement in the direction lengthwise of the path, said latch membertaking the form of a shaft incorporated in a servomechanism for anoperating unit which is mounted in the cartridge, and said shaft beingreciprocable and having a flange thereon, so that the operating unit canbe actuated by uni-directional forces applied to the flange, through thecap, in the direction of reciprocation of the shaft, relatively inwardof the cartridge, and said cartridge having a mechanism incorporatedtherein whereby the force applied to the flange, operates alternately tolatch the servomechanism in the operating position thereof, and torelease the servomechanism from the operating position thereof, saidalternate action mechanism being slidably engaged on the shaft, betweenthe flange and the cap, and the cap being yieldably biased in thedirection of reciprocation, relatively outward of the cartridge, so thatthe cap is shifted between alternate positions relatively inward andoutward of the cartridge, when the servomechanism is latched in andreleased from the operating position thereof.
 34. In combination, anopen-ended cartridge having a latch member therein, and a cap which isslidably guided in the open end of the cartridge to engage and disengagethe member, said cap defining a stop about the path of engagement anddisengagement of the member, a latch element which is reciprocable inparallel with the cap, as well as independently thereof, and which isyieldably biased in a direction lengthwise of the path of engagement anddisengagement of the member, into engagement with the stop, as well asyieldably biased in a direction transverse of the path, to assume aposition thereon, detent means which are operable to interengage thelatch element and the member, when the member is engaged with the capagainst the bias on the element in the direction transverse of the path,and latch release means which are operable to disengage the latchelement and the member, when the member is disengaged from the capagainst the bias on the latch element in the direction lengthwise of thepath, said latch member taking the form of a shaft incorporated in aservomechanism for an operating unit which is mounted in the cartridge,and said servomechanism including an intermediate actuator which isinterposed between the shaft and the operating unit, and operable toactuate the unit while providing a degree of over-travel for the shaftin the operating stroke thereof.